A person who travels around suburban areas and subdivisions at night around Christmas to gaze at other people's outdoor Christmas light displays on their homes and around their yards. When word gets around that a particular house is highly festooned with a large, elaborate display (sometimes even synchronized to music that can be heard by tuning to a short-range FM radio frequency within close vicinity of said house), traffic congestion will often result. These people are similar to leafers.
Person 1: "Boy, the Griswolds sure have one hell of a Christmas light display this year!"
Person 2: "Yeah, but look at all the bulbers who have come out to look at it!"